Endoscope

ABSTRACT

There is provided an endoscope capable of realizing equal operability by either a left or right hand without upsizing an operation portion. For this purpose, an operation portion is formed in a bilaterally symmetrical shape; a suction button and a bending lever are disposed at a center in a left and right width direction of the operation portion facing each other; and respective arm portions are disposed in a state of being rotated around a central axis of the bending lever by a predetermined angle relative to up, down, left and right tilt directions defined for the bending lever.

CROSS REFERENCE TO RELATED APPLICATION

This application is a continuation application U.S. patent applicationSer. No. 15/201,703 filed on Jul. 5, 2016 which is a continuation ofPCT/JP2015/058328 filed on Mar. 19, 2015 and claims benefit of JapaneseApplication No. 2014-102625 filed in Japan on May 16, 2014, the entirecontents of each of which are incorporated herein by this reference.

BACKGROUND OF INVENTION 1. Field of the Invention

The present invention relates to an endoscope in which a bending portionperforms a bending motion in conjunction with an operation of tilting abending lever.

2. Description of the Related Art

Conventionally, endoscopes have been widely used in medical andindustrial fields. Some endoscopes are provided with an elongated andflexible insertion portion. In general, such flexible endoscopes areprovided with a bending portion capable of freely performing a bendingmotion in a predetermined direction in accordance with a user's manualoperation, on a distal end side of the insertion portion.

Among the endoscopes, especially in a small-diameter endoscope for whichan amount of force for bending is small, and the bending portion ofwhich bends with a small radius of curvature, such as a bronchialendoscope, each portion is generally configured so that a graspingportion provided on the operation portion is grasped by three fingers ofa middle finger, a third finger and a little finger of a left hand, abending lever is operated by a thumb, and various kinds ofswitches/buttons such as a suction button are operated by a forefinger.Further, in order to easily realize a similar operation not only by aleft hand but also by a right hand on an endoscope of this kind, forexample, Japanese Patent Application Laid-Open Publication No. H8-299255discloses a technique in which the bending lever is extended backwardfrom a side portion of the operation portion in an L shape, a fingerhooking portion is disposed on a back side of the operation portion, anda suction button is disposed on a longitudinal-direction central axis ofthe operation portion, on a switch portion set on a front side of theoperation portion.

By the way, as for the endoscope with a small diameter, such as abronchial endoscope, it is also demanded to cause the bending portion toperform a bending motion not only in two directions, such as up and downdirections, but also in any of directions including up, down, left andright directions. As a technique for realizing such a bending motion byan operation input to a single bending lever, for example, JapanesePatent Application Laid-Open Publication No. 2003-325437 discloses abending apparatus provided with a wire pulling member having four armportions to which proximal end portions of pulling wires (pullingmembers) corresponding to up, down, left and right bending directionsare fixed, respectively, and an operation instruction lever (bendinglever) for giving an instruction to cause a tilt direction of and anamount of tilt of the wire pulling member to change and cause apredetermined pulling wire, among the respective pulling wires, to moveby a predetermined amount.

SUMMARY OF THE INVENTION

An endoscope according to an aspect of the present invention includes:an insertion portion insertable into a subject and having a bendingportion bendable in all directions including four directions of up,down, left and right directions with a longitudinal axis as a center;four wires configured to cause the bending portion to bend by pulling,distal end sides of the four wires being inserted through the insertionportion; an operation portion linked to a proximal end of the insertionportion; an operation button projectingly disposed at a center in a leftand right width direction of the operation portion; a button linkingmember provided in the operation portion and linked to the operationbutton; an operation lever disposed at the center in the left and rightwidth direction of the operation portion so that the operation lever andthe operation button face each other in front and behind, and tiltablein all directions including four directions corresponding to the up,down, left and right directions of the bending portion; and a wirepulling member tiltably provided in the operation portion, the operationlever being coupled with a central part of the wire pulling member, andproximal end sides of the wires being coupled with respective distal endsides of four arm portions extended in cross directions from the centralpart; wherein tilt directions of the operation lever for causing thebending portion to bend in the up, down, left and right directions areset to correspond to four directions of the left and right widthdirections of the operation portion and directions orthogonal to theleft and right width directions, respectively; extending directions ofthe four arm portions of the wire pulling member are disposed atpositions rotated around a central axis of the operation lever by a setangle relative to the four tilt directions set for the operation lever;and the button linking member is provided at a position facing the wirepulling member and is positioned between and faced by two arm portionsamong the four arm portions so that the four arm portions do notinterfere with the button linking member.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front view showing an external appearance of an endoscope;

FIG. 2 is a right side view showing the external appearance of theendoscope;

FIG. 3 is a top view showing the external appearance of the endoscope;

FIG. 4 is an explanatory diagram showing an arrangement relationshipbetween a wire pulling member and a cylinder;

FIG. 5 is a perspective view showing an arrangement relationship betweena bending operation mechanism and the cylinder;

FIG. 6 is a perspective view showing an internal structure body of thebending operation mechanism;

FIG. 7 is an exploded perspective view showing the internal structurebody of the bending operation mechanism;

FIG. 8 is a cross-sectional view showing main portions of a distal endportion and a bending portion;

FIG. 9 is a sectional view showing the distal end portion along a IX-IXline in FIG. 8;

FIG. 10 is a sectional view showing the bending portion along a X-X linein FIG. 8; and

FIG. 11 is a sectional view showing the bending portion along an XI-XIline in FIG. 8.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT(S)

An embodiment of the present invention will be described with referenceto drawings. The drawings are related to the embodiment of the presentinvention. FIG. 1 is a front view showing an external appearance of anendoscope; FIG. 2 is a right side view showing the external appearanceof the endoscope; FIG. 3 is a top view showing the external appearanceof the endoscope; FIG. 4 is an explanatory diagram showing anarrangement relationship between a wire pulling member and a cylinder;FIG. 5 is a perspective view showing an arrangement relationship betweena bending operation mechanism and the cylinder; FIG. 6 is a perspectiveview showing an internal structure body of the bending operationmechanism; FIG. 7 is an exploded perspective view showing the internalstructure body of the bending operation mechanism; FIG. 8 is across-sectional view showing main portions of a distal end portion and abending portion; FIG. 9 is a sectional view showing the distal endportion along a IX-IX line in FIG. 8; FIG. 10 is a sectional viewshowing the bending portion along a X-X line in FIG. 8; and FIG. 11 is asectional view showing the bending portion along an XI-XI line in FIG.8.

An endoscope 1 of the present embodiment shown in FIGS. 1 and 2 is abronchial electronic endoscope, and the endoscope 1 is configured havingan insertion portion 2 formed in an elongated tube shape, an operationportion 3 linked to a proximal end of the insertion portion 2, auniversal cord 4, which is an endoscope cable disposed extending fromthe operation portion 3, and an endoscope connector 5 disposed at adistal end of the universal cord 4.

The insertion portion 2 is configured with a tubular member havingflexibility to which a distal end portion 6, a bending portion 7 and aflexible tube portion 8 are linked in this order from the distal endside.

For example, as shown in FIGS. 8 and 9, a distal end rigid portion 10made of metal is provided in the distal end portion 6, and, in thedistal end rigid portion 10, an image pickup unit 11 which includes animage pickup device such as a CCD and a CMOS, a pair of light guides 12and a treatment instrument insertion channel 13 are held.

Further, in the distal end portion 6, a most distal end bending piece 20forming a substantially cylindrical shape is fitted on a proximal endside of the distal end rigid portion 10, and an outer circumference ofthe most distal end bending piece 20 is covered with bending rubber 22.On an inner circumference of the most distal end bending piece 20, wirefixing portions 21 are provided at four positions around an insertionaxis O. A distal end of any one of four pulling wires 23 insertedthrough the insertion portion 2 is fixed to each of the wire fixingportions 21.

Here, in order to efficiently dispose each component member withoutincreasing a diameter of the distal end portion 6, the image pickup unit11, which is a large-sized member, and the treatment instrumentinsertion channel 13 are arranged side by side on right and left in thedistal end rigid portion 10 and the most distal end bending piece 20(see FIGS. 8 and 9), and the respective light guides 12 are disposed inspaces formed above and below by the arrangement. Note that, in thepresent embodiment, up, down, left and right directions of the distalend portion 6 (insertion portion 2) are, for example, directions definedto correspond to up, down, left and right directions of an image pickedup by the image pickup unit 11.

Further, in order to prevent interference of the image pickup unit 11and the treatment instrument insertion channel 13 with each pulling wire23, the respective wire fixing portions 21 are provided at positionsrotated around the insertion axis O by a predetermined angle relative tothe up, down, left and right positions of the distal end portion 6. Thatis, for example, as shown in FIG. 9, the most distal end bending piece20 is provided with the respective wire fixing portions 21 at positionsrotated left and right, respectively, around the insertion axis O by anangle within a range of 30 to 60 degrees (more specifically, forexample, positions rotated left and right by 39 degrees, respectively),with the up direction of the distal end portion 6 as a reference, andpositions rotated left and right, respectively, around the insertionaxis O by an angle within the range of 30 to 60 degrees (morespecifically, for example, positions rotated left and right by 39degrees, respectively), with the down direction of the distal endportion 6 as a reference. In other words, the respective pulling wires23 are routed at positions rotated around the insertion axis O by apredetermined angle relative to the up, down, left and right directions,respectively, in the distal end portion 6.

The bending portion 7 is configured so that the bending portion 7 can becaused to actively bend in all circumferential directions around theinsertion axis O, including the up, down, left and right directions, inresponse to an operation input to the operation portion 3 by a surgeonor the like. That is, the bending portion 7 of the present embodiment isconfigured having a bending piece set 24, for example, in which aplurality of bending pieces 25 are linked and which has pivoted portions25 a disposed in the up and down directions of the insertion portion 2(see FIG. 8) on a distal end side, and pivoted portions 25 b disposed inthe left and right directions of the insertion portion 2 on a proximalend side.

Inside the bending piece set 24, a signal cable 11 a which extend fromthe image pickup unit 11, the light guides 12 and the treatmentinstrument insertion channel 13 are inserted in an arrangementsubstantially similar to an arrangement in the distal end portion 6.Further, an outer circumference of the bending piece set 24 is coveredwith the bending rubber 22 extending from a distal end portion 6 side.

Further, on a predetermined bending piece 25 constituting the bendingpiece set 24, wire guides 26 in which the respective pulling wires 23are to be inserted are formed. Similarly to the wire fixing portions 21described above, the wire guides 26 are provided at positions rotatedaround the insertion axis O by a predetermined angle relative to up,down, left and right positions of the bending portion 7. That is, forexample, as shown in FIGS. 10 and 11, the predetermined bending piece 25is provided with the respective wire guides 26 at positions rotated leftand right, respectively, around the insertion axis O by an angle withina range of 30 to 60 degrees (more specifically, for example, positionsrotated to a left side by 34 degrees and to a right side by 44 degrees,respectively) with the up direction of the bending portion 7 as areference, and positions rotated left and right, respectively, aroundthe insertion axis O by an angle within the range of 30 to 60 degrees(more specifically, for example, positions rotated to the left side by42 degrees and to the right side by 45 degrees, respectively) with thedown direction of the bending portion 7 as a reference. In other words,the respective pulling wires 23 are routed at positions rotated aroundthe insertion axis O relative to the up, down, left and rightdirections, respectively, in the bending portion 7.

The flexible tube portion 8 is configured with a tubular member havingflexibility of being passively bendable. Inside the flexible tubeportion 8, the signal cable 11 a, light guides 12 and treatmentinstrument insertion channel 13 described above are inserted (none ofthem is shown here).

The operation portion 3 is configured having a bend preventing portion30 connected to the flexible tube portion 8 in a state of covering aproximal end of the flexible tube portion 8, a grasping portion 31 whichis linked to the bend preventing portion 30 and which can be grasped bya hand of a user or the like, and an operation portion body 32 linked toa proximal end side of the grasping portion 31. Note that, in thepresent embodiment, the directions or the like around the insertion axisO in the operation portion 3 are defined based on a state of the user orthe like grasping the grasping portion 31, and, more specifically,forward, backward, left and right directions (front, back, left andright side faces, and the like) based on the user or the like graspingthe grasping portion 31 are defined for the operation portion 3.

As shown in FIG. 1, the grasping portion 31 is formed in a bilaterallysymmetrical shape relative to the insertion axis O (the central axis),and the user or the like can grasp the grasping portion 31 by either aleft hand or a right hand similarly.

Further, a treatment instrument insertion portion 35 is provided on afront on a distal end side of the grasping portion 31. The treatmentinstrument insertion portion 35 is configured having a treatmentinstrument insertion port 35 a through which various kinds of treatmentinstruments (not shown) are to be inserted. Inside the operation portion3, the treatment instrument insertion channel 13 is communicated to thetreatment instrument insertion port 35 a via a branch member not shown.Further, a forceps plug (not shown), which is a cover member forblocking the treatment instrument insertion port 35 a, can be detachablyattached to the treatment instrument insertion portion 35.

The operation portion body 32 is configured with a hollow member forminga substantially partially spherical shape which is swollen mainly towardleft and right sides and forward, on the proximal end side of thegrasping portion 31. On a front side of the operation portion body 32,an operation button group 40 for executing various kinds of functions ofthe endoscope 1 is disposed. On the other hand, a bending lever 45 as anoperation lever for performing a bending operation of the bendingportion 7 is disposed on a back side of the operation portion body 32.Furthermore, the universal cord 4 is extended from one side portion (forexample, a left side portion) of the operation portion body 32.

Here, a left and right shape of the operation portion body 32 is a shapeswollen bilaterally symmetrically relative to the insertion axis O. Onleft and right side faces on a distal end side of the operation portionbody 32, guiding recess portions 32 a for guiding the forefinger or thelike of the user grasping the grasping portion 31 to the operationbutton group 40 are formed, respectively.

The universal cord 4 extends up to the operation portion 3 from thedistal end portion 6 side through the inside of the insertion portion 2,and it is, furthermore, a composite cable in which various kinds ofsignal lines extending from the operation portion 3, the light guides 12of a light source apparatus (not shown) and, furthermore, an air/waterfeeding tube extended from an air/water feeding apparatus (not shown)are inserted inside.

The endoscope connector 5 is configured having an electric connectorportion 5 a to which a signal cable for connecting to a video processor(not shown), which is an external apparatus, is connected, on a sideface portion as well as having a light source connector portion 5 b towhich the light guides and electric cables connecting to the lightsource apparatus, which is an external apparatus, are connected, and anair/water feeding plug 5 c for connecting an air/water feeding tube (notshown) from the air/water feeding apparatus (not shown), which is anexternal apparatus.

Next, a configuration of each portion in the operation portion body 32will be described in more detail.

As shown in FIG. 1, the operation button group 40 is configured having,for example, a suction button 41 a as an operation button projectingfrom a suction valve 41 detachably fitted to the operation portion body32, and two button switches 42 to which arbitrary functions among thevarious kinds of functions of the endoscope 1 can be allocated.

The suction button 41 a and the button switches 42 are arranged so as tobe bilaterally symmetrical on the front side of the operation portionbody 32. That is, in the present embodiment, the suction button 41 a isdisposed at a center in a left and right width direction of theoperation portion body 32 so as to be superposed on the insertion axisO. Further, the two button switches 42 are disposed at positionsbilaterally symmetrical, with the insertion axis O sandwiched betweenthem, on a more distal end side than the suction button 41 a.

Here, for example, as shown in FIG. 4, a cylinder 43 as a button linkingmember to be linked to the suction valve 41 is provided inside theoperation portion body 32. The cylinder 43 is adapted so that thesuction valve 41 can be detachably fitted to the cylinder 43, and isdisposed at the center in the left and right width direction of theoperation portion body 32 so as to be superposed on the insertion axis Oto correspond to the disposition of the suction button 41 a.

The bending lever 45 is configured with a joystick type lever, forexample, tiltable in all directions including the up, down, left andright directions. The bending lever 45 is disposed at a position wherethe bending lever 45 is bilaterally symmetrical, on the back side of theoperation portion body 32. That is, in the present embodiment, thebending lever 45 is disposed at the center in the left and right widthdirection of the operation portion body 32 so as to be superposed on theinsertion axis O. Here, as for the tilt directions of the bending lever45, for example, the left and right directions of tilt operations aredefined as the left and right width direction of the operation portion3, which is a direction orthogonal to the insertion axis O, and the upand down directions of tilt operations are defined as a directionorthogonal to the left and right width direction, for example, as shownin FIG. 3.

More specifically, the tilt directions of the bending lever 45 of thepresent embodiment are respectively defined as follows, for example: aleft side of FIG. 3 is a tilt direction for causing the bending portion7 to bend to the left side (a left tilt direction); a right side of FIG.3 is a tilt direction for causing the bending portion 7 to bend to theright side (a right tilt direction); a lower side of FIG. 3 is a tiltdirection for causing the bending portion 7 to bend to an upper side (anup tilt direction); and an upper side of FIG. 3 is a tilt direction forcausing the bending portion 7 to bend to a lower side (a down tiltdirection).

A finger contact portion 46 which the thumb or the like of the user orthe like can be caused to abut is provided at a tip end portion of thebending lever 45. Further, a bending operation mechanism 50 is coupledwith a proximal end side of the bending lever 45 inside the operationportion 3, and the bending lever 45 is capable of causing the bendingportion 7 to bend in an arbitrary direction via a pulling motion of eachpulling wire 23 performed by the bending operation mechanism 50.

As shown in FIGS. 5 to 7, the bending operation mechanism 50 isconfigured having a housing 51 forming a substantially cylindricalshape, a rotation frame 52 which is pivotally supported so as to berotatable (swingable) in the housing 51, a base member 53 which ispivotally supported so as to be rotatable (swingable) in the rotationframe 52, and a wire pulling member 54 fixed to the base member 53.

The housing 51 is configured with a member forming a substantiallycylindrical shape, and shaft holes 51 a facing each other are made in aperipheral wall of the housing 51.

The rotation frame 52 is configured with a frame body, for example,forming a substantially rectangular shape. At centers of bothlongitudinal-direction end portions of the rotation frame 52, a pair ofscrew holes 52 a facing each other are made, and, furthermore, atcenters of both lateral-direction end portions, a pair of shaft holes 52b facing each other are made. By screws 55 inserted in the respectiveshaft holes 51 a of the housing 51, respectively, being screwed with therespective screw holes 52 a, the rotation frame 52 is pivotallysupported to be rotatable relative to the housing 51.

The base member 53 is configured with a member forming a substantiallycylindrical shape. A fitting hole 53 a is made at a central part of thebase member 53, and the proximal end side of the bending lever 45 iscoupled with the fitting hole 53 a by insertion. Further, a pair of flatportions 53 b facing each other are formed on a peripheral portion ofthe base member 53, and screw holes 53 c facing each other (in FIG. 7,only one of the screw holes 53 c is shown) are made in the flat portions53 b. By screws 56 inserted in the respective shaft holes 52 b of therotation frame 52, respectively, being screwed with the respective screwholes 53 c, the base member 53 is pivotally supported to be rotatablerelative to the rotation frame 52. By the base member 53 being supportedby the housing 51 via the rotation frame 52 in this way, the bendinglever 45 coupled with the base member 53 can tilt in an arbitrarydirection.

The wire pulling member 54 is configured with a plate-like member fromwhich arm portions 54 b are extended in four directions mutuallydifferent from one another. More specifically, in the presentembodiment, the wire pulling member 54 is configured with a cross-shapedplate-like member in which an angle formed by mutually adjoining armportions 54 b is set to be 90 degrees, and central part 54 a is fixed tothe base member 53 via screws 57. That is, the bending lever 45 iscoupled with the wire pulling member 54 via the base member 53. Further,on distal end sides of the respective arm portions 54 b, wire fixingholes 54 c are made, and proximal end sides of the respective pullingwires 23 extended from an insertion portion 2 side are fixed to the wirefixing holes 54 c. Thereby, the wire pulling member 54 can pull apredetermined pulling wire 23 corresponding to a tilt state of thebending lever 45 by a predetermined amount of pulling. Note that, theangle formed by the respective arm portions 54 b is not limited to 90degrees. For example, the angle can be arbitrarily changed within arange of 90 degrees±30 degrees.

The bending operation mechanism 50 configured as described above isdisposed so that the bending operation mechanism 50 faces the cylinder43 in front and behind in the operation portion body 32. In this case,in the bending operation mechanism 50, the respective arm portions 54 bare disposed at positions rotated around a central axis OI of thebending lever 45 by an angle within a range of 30 to 60 degrees (forexample, positions rotated by 45 degrees) relative to the up, down, leftand right tilt directions defined for the bending lever 45. Thereby, forexample, as shown in FIG. 4, the bending operation mechanism 50 isarranged in a state that the cylinder 43 is positioned between and facedby two arm portions 54 b of the wire pulling member 54.

Furthermore, for example, as shown in FIG. 5, two respective stays 58extending to both sides of the cylinder 43 are provided on the housing51 of the bending operation mechanism 50; guide coils 23 a are fixed tothe stays 58; and each pulling wire 23 is inserted in the guide coils 23a so that the pulling wire 23 is routed, taking a detour to avoidinterference with the cylinder 43.

In such a configuration, for example, when the user or the like graspsthe grasping portion 31 of the operation portion 3 and causes thebending lever 45 to tilt in the left tilt direction by the thumb of thehand grasping the grasping portion 31, mainly pulling wires 23 coupledwith two arm portions 54 b located in the right tilt direction arepulled. Thereby, mainly two pulling wires 23 located on a left side of abending direction are pulled in the bending portion 7, and the bendingportion 7 is bent to a left side.

Further, for example, when the user or the like grasps the graspingportion 31 of the operation portion 3 and causes the bending lever 45 totilt in the right tilt direction by the thumb of the hand grasping thegrasping portion 31, mainly pulling wires 23 coupled with two armportions 54 b located in the left tilt direction are pulled. Thereby,mainly two pulling wires 23 located on a right side of a bendingdirection are pulled in the bending portion 7, and the bending portion 7is bent to a right side.

Further, for example, when the user or the like grasps the graspingportion 31 of the operation portion 3 and causes the bending lever 45 totilt in the up tilt direction by the thumb of the hand grasping thegrasping portion 31, mainly pulling wires 23 coupled with two armportions 54 b located in the down tilt direction are pulled. Thereby,mainly two pulling wires 23 located on an upper side of a bendingdirection are pulled in the bending portion 7, and the bending portion 7is bent to an upper side.

Further, for example, when the user or the like grasps the graspingportion 31 of the operation portion 3 and causes the bending lever 45 totilt in the down tilt direction by the thumb of the hand grasping thegrasping portion 31, mainly pulling wires 23 coupled with two armportions 54 b located in the up tilt direction are pulled. Thereby,mainly two pulling wires 23 located on a lower side of a bendingdirection are pulled in the bending portion 7, and the bending portion 7is bent to a lower side.

Furthermore, by the user or the like guiding the forefinger or the likeof the hand grasping the operation portion 3 along the guiding recessportions 32 a to the operation button group 40 and performing a pressingoperation of the suction button 41 a and the like while grasping theoperation portion 3, the various kinds of functions by the endoscope 1,such as a suction motion, are executed.

At that time, by the operation portion 3 (the grasping portion 31)forming a bilaterally symmetrical shape, and the suction button 41 a andthe bending lever 45 being arranged facing each other at the center inthe left and right width direction of the operation portion 3 (theoperation portion body 32), it is possible to grasp the operationportion 3 similarly by either the left or right hand, and, moreover, itis possible to manually operate the suction button 41 a and the bendinglever 45 with equal operability. In this case, since the respective armportions 54 b are disposed in a state of being rotated around thecentral axis OI of the bending lever 45 by a predetermined anglerelative to the up, down, left and right tilt directions defined for thebending lever 45, it is possible to prevent the arm portions 54 b andthe like from interfering with the cylinder 43. Especially, even whenthe bending lever 45 is caused to be tilted in the up or down tiltdirection, it is possible to prevent the arm portions 54 b, the pullingwires 23 and the like which are linked with the tilt from interferingwith the cylinder 43. Therefore, it is possible to arrange the suctionbutton 41 a and the bending lever 45 facing each other in front andbehind at the center in the left and right width direction of theoperation portion 3, without causing the wire pulling member 54 (thebending operation mechanism 50) to be considerably separated from thecylinder 43, and it is possible to realize equal operability by either aleft or right hand without upsizing the operation portion 3.

Further, even when the tilt directions of the bending lever 45 arecaused to be different from the extending directions of the respectivearm portions 54 b, around the central axis OI of the bending lever 45 onthe operation portion 3 side, it is possible to, by routing the pullingwires 23 to be routed in the bending portion 7 at positions rotatedaround the insertion axis O by a set angle relative to the up, down,left and right bending directions of the bending portion 7 substantiallyaccording to the above state, easily cause the up, down, left and rightbending directions of the bending portion 7 to correspond to the up,down, left and right tilt directions defined for the bending lever 45.Furthermore, since it is not necessary to route the pulling wires 23 inthe left and right directions in the bending portion 7 if the abovedisposition is adopted, it is possible to, for example, by using alayout in a bending portion capable of bending only in the up and downdirections, in which the image pickup unit 11 which is a large-sizedmember and the treatment instrument insertion channel 13 are arrangedside by side on right and left as it is, realize bending motions in theup, down, left and right directions without increasing an outerdiameter.

Note that the present invention is not limited to each embodimentdescribed above, and various modifications and changes are possible. Themodifications and changes are also within the technical scope of thepresent invention. For example, though description has been made on anexample in which the present invention is applied to a bronchialendoscope in the embodiment described above, the present invention isnot limited to that and is also applicable, for example, to a urinaryendoscope or the like.

Further, it goes without saying that the tilt directions defined for thebending lever are not limited to those described above and that theoperation buttons are not limited to the suction button and the like.

What is claimed is:
 1. An endoscope comprising: an insertion portion insertable into a subject and comprising a bending-portion bendable in all directions including four directions of up, down, left and right directions with a longitudinal axis as a center; four wires configured to cause the bending portion to bend by pulling, distal end sides of the four wires being inserted through the insertion portion; an operation portion linked to a proximal end of the insertion portion; an operation button projectingly disposed at a center in a left and right width direction of the operation portion; a button linking member provided in the operation portion and linked to the operation button; an operation lever disposed at the center in the left and light width direction of the operation portion so that the operation lever and the operation button face each other as viewed from a front and back of the operation portion, the operation portion being tiltable in all directions including four directions corresponding to the up, down, left and right directions of the bending portion; and a wire pulling member including a central part to which one end of the operation lever is connected, the wire pulling member including four fixing portions in a periphery portion of the central part, the four wires being respectively fixed to the four fixing portions, and a housing formed in a substantially cylindrical shape, the wire pulling member being disposed inside the housing, the housing supporting the wire pulling member rotatably around two axes orthogonal to each other, the housing being arranged at a center in the left and right width direction of the operation portion, the housing being arranged to adjoin the button linking member, wherein two wires of the four wires are disposed on a right side of the button linking member, and an other two wires of the four wires are disposed on a left side of the button linking member.
 2. The endoscope according to claim 1, wherein each of the four wires is inserted through a guide coil.
 3. The endoscope according to claim 2, wherein the guide coil is fixed to the housing. 